Methods and systems for occluding vessels during cardiac ablation including optional electroanatomical guidance

ABSTRACT

A method is provided for ablating a portion of the myocardium. The method includes inserting an occlusion catheter into a vessel on a heart, occluding the vessel using the occlusion catheter, inserting an ablation catheter into a chamber of the heart, positioning the ablation catheter against the myocardium, and ablating a portion of the myocardium while the vessel is occluded. The system includes an occlusion catheter having a catheter body including a tubular member having a distal portion and a bend located in the distal portion, a balloon located proximal of the bend and configured to contact an inner surface of the CS when positioned therewithin, a plurality of marker bands positioned on the catheter body, and a plurality of electrodes positioned on the catheter body. One or more electrodes or coils can be used as a reference for an electroanatomical system and can be disposed on the occlusion catheter.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/785,227 filed 21 May 2010 (the '227 application), which claims thebenefit of U.S. provisional patent application No. 61/232,260 filed 7Aug. 2009 (the '260 application); and which is a continuation-in-part ofinternational patent application no. PCT/US2008/084406 filed 21 Nov.2008 (the '406 application), which in turn claims the benefit of U.S.provisional application No. 60/989,807 filed 21 Nov. 2007, (the '807application). The '227, the '260, the '406, and the '807 applicationsare hereby incorporated by reference as though fully set forth herein.This application is also related to U.S. patent application Ser. No.12/785,140, filed 21 May 2010, the contents of which are also fullyincorporated herein.

BACKGROUND OF THE INVENTION a. Field of the Invention

The field of the invention relates generally to cardiac ablation, and,more particularly, to vascular occlusion during cardiac ablationprocedures including optional electroanatomical guidance during saidprocedures.

b. Description of Related Art

Atrial fibrillation is a form of arrhythmia and results fromdisorganized electrical activity in the heart muscle, or myocardium. Asa result of abnormalities in the heart's electrical activity, the heartdoes not beat effectively and it is not able to pump the blood outproperly.

Ablation of the mitral isthmus, defined as a narrow region between themitral annulus and the left inferior pulmonary vein ostium, appears toincrease the success rate of treating chronic atrial fibrillation.However, it is difficult to create transmural lesions in this region,even though the myocardial thickness in the mitral isthmus is notparticularly greater than in other regions of the left atrium.Incomplete or non-continuous lesions and/or unidirectional mitralisthmus block can be problematic as it may result in recurrence ofarrhythmia and/or a proarrhythmic effect by slowing conduction throughthe mitral isthmus. High-power endocardial ablations, as well asdelivery of radio frequency (RF) energy into the coronary sinus (CS) andthe great cardiac vein (epicardial portion of the mitral isthmus), arefrequently used to prevent incomplete lines. This combinedepicardial/endocardial approach sometimes allows for bidirectionalisthmus block to be achieved but includes certain risks and complexitiesrelating to anatomy near the mitral isthmus and the effects of bloodflowing through the CS also near the mitral isthmus.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, an inventive method is provided for ablating a portion ofthe myocardium. The method includes inserting an inventive occlusioncatheter into a vessel on a heart, occluding the vessel using theocclusion catheter, inserting an ablation catheter into a chamber of theheart, positioning the ablation catheter against the myocardium, andablating a portion of the myocardium while the vessel is occluded. Theocclusion catheter includes electrodes which can be used forvisualization (e.g., via fluoroscopy, impedance- or magnetic-basedelectroanatomical visualization and location systems, and the like).

In another aspect, a method is provided for ablating a portion of theatrial myocardium. The method includes inserting a balloon catheter intoa CS, inserting an ablation catheter into a left atrium of a heart, andablating a portion of the atrial myocardium while a balloon, orexpandable film of material or the like (herein “balloon”) on theballoon catheter is expanded.

In a further aspect, an occlusion catheter is provided that includes acatheter body including a tubular member having a distal portion and abend located in the distal portion. The occlusion catheter also includesa balloon located proximal of the bend and configured to contact aninner surface of the CS when positioned therewithin. A plurality ofmarker bands are positioned on the catheter body and a plurality ofelectrodes and/or metallic coils also are positioned on the catheterbody to promote fluoroscopic visualization and localization andvisualization via an electroanatomical system, respectively. The bendcan promote anchoring of the occlusion catheter in a desired positionrelative to the os of the CS. A selectable one of the plurality ofactive electrodes and/or metallic coils can be selected as a referencenode for an impedance- or magnetic-based electroanatomical system,respectively. That is, at least one of orientation, location andposition of can be determined for other catheters, such as ablationcatheters, relative to the reference node. If the other catheter(s)include at least three electrodes or coils (e.g., tip- or ring-typeelectrodes, metallic coils and the like) and the type of catheter andspacing of the elements is known the catheter can be simulated in thecontext of a 3D geometry generated by a roving catheter. The shaft ofthe catheter having the selected reference node can be simulated in vivoas well as various mapping and therapy delivery and sensing/imagingcatheters, if desired. The spacing between active elements, such aselectrodes provides relative spatial reference information and allowsthe 3D geometry of an organ, such as a heart, to have dimensions scaledto the actual dimensions.

Accordingly, the present disclosure provides devices and methods foranchoring a reference electrode or a magnetic coil or the like for use,for example, in an electroanatomical myocardial mapping or ablationprocedure. The present disclosure also provides devices and methods foranchoring a reference electrode within a vessel while preserving adegree of perfusion through the vessel, if desired. Another aspect ofthe present disclosure provides devices and methods to anchor anelectrode within a vessel for use in diagnostic and/or therapeuticprocedures.

Thus, herein described, depicted, and claims are catheters for anchoringan electrode in a portion of a CS, such as a portion of the great veinstemming therefrom. Such a catheter can include: an elongate catheterbody adapted to be inserted into a portion of a vessel coupled to the CSand/or the great cardiac vein, the elongate catheter body including ananchor section having an expandable axial cross-section; at least onemarker band or electrode disposed on the catheter body; and an actuationmechanism operably coupled to the anchor section to actuate the anchorsection between an undeployed configuration, wherein the expandableaxial cross-section of the anchor section is in a collapsed or unbentstate, and a deployed configuration, wherein the anchor section is in anexpanded or bent state. When the anchor section is in the deployedconfiguration, for example, an expandable axial cross-section can engagea tissue surface of the CS to inhibit movement between the catheter bodyand the CS without necessarily completely occluding the CS such that theat least one electrode or marker band remain in a stable, or reference,position. The at least one electrode or marker band may be positioneddistally of the anchor section, proximally of the anchor section, in anessentially linear array, and/or on or as a minor part of the anchorsection.

In some embodiments, the catheter body includes at least one perfusionpassage having a first opening positioned distally of the anchor sectionand a second opening positioned proximally of the anchor section. Thispermits a degree of perfusion through the interior of the catheter body,if desired. Alternatively, or in addition, the catheter may beconfigured so that the degree of perfusion occurs through the vesselaround the exterior of the catheter body and/or cause the distal tip tobend or deflect. Thus, for a medical procedure that takes an extendedperiod of time the degree of permitted perfusion can be reduced orincreased, or complete occlusion can be established, as required ordesired as the procedure proceeds.

Optionally, the actuation mechanism includes a tension member. Placingthe tension member in tension may cause the anchor section to assume adeployed or bent configuration.

In some embodiments of the invention, the anchor section includes atleast one expandable member mounted to an outer surface of the catheterbody to both occlude the CS and anchor the catheter at the same time.The at least one expandable member may include at least one balloon, atleast one basket or umbrella-shaped structure, or at least one otherexpandable structure (e.g., at least one sleeve or a fluidly expandablefilm of material or the like).

Thus, disclosed herein is a catheter for anchoring an electrode in astable position relative to a CS, including: an elongate catheter bodyadapted to be inserted into a portion of the CS or vein extendingtherefrom; at least one partial- or completely-occluding anchor(“anchor”) structure coupled to the catheter body; and at least oneelectrode on the catheter body. The at least one anchor is movablebetween an undeployed configuration, wherein the catheter body ismovable relative to the CS, and a deployed configuration, wherein the atleast one anchor engages a tissue surface of the CS to inhibit movementbetween the catheter body and the CS at least partially, if notnecessarily completely occluding the CS.

According to another aspect of the invention, a catheter for anchoringan electrode in or to a peripheral portion of the CS includes: anelongate catheter body having a central axis and a flexible anchorsegment, the flexible anchor segment being movable between a deployedconfiguration, wherein the flexible anchor segment is deviated from thecentral axis of the catheter body to engage a tissue surface of the CSsuch that relative movement between the catheter body and the CS isinhibited without necessarily completely occluding the CS, and anundeployed configuration, wherein the flexible anchor segment isgenerally collinear with the central axis of the catheter body tointroduce the catheter into the coronary sinus; and at least one markerband or electrode on the catheter body. Although complete orsubstantially complete occlusion is typically a more desirablecondition, especially for mitral isthmus ablation procedures, asdescribed more fully herein.

In some embodiments of the invention, the flexible anchor segment isbiased into the undeployed configuration, and the catheter furtherincludes a tension member. By placing the tension member in tension, theflexible anchor segment may be moved into the deployed configuration. Inother embodiments of the invention, the flexible anchor segment isbiased into the deployed configuration, and a sheath, stylet, guidewire, or other suitable straightening device may be used to move theflexible anchor segment into the undeployed configuration. Of course,the flexible anchor segment may be positioned as desired along thecatheter body, including within an intermediate section of the catheterbody or at the distal end of the catheter body and includes at least one(active) marker band or electrode to be selectable as a spatialreferences for generation of geometries or models and for visualizationin conjunction with other active elements using an electroanatomicalsystem.

The present invention also provides a method of generating a cardiacgeometry, including the steps of: providing a CS catheter having ananchor structure and at least one marker band or electrode thereon;introducing the CS catheter into the CS or portion thereof; deployingthe anchor structure to engage at least one tissue surface of thecoronary sinus, thereby inhibiting relative movement between the CScatheter and the CS; and conducting a cardiac mapping operation usingthe electrode on the CS catheter as a reference electrode.

An advantage of the present invention is that it permits a referenceelectrode to be positively anchored within a vessel, therebyfacilitating creation of anatomical geometries during or prior toperforming a medical procedure (e.g., cardiac mapping and/or ablation).Another advantage of the present invention is that it positively anchorsa reference electrode within a vessel while optionally preserving adegree of perfusion through the vessel, if desired to limit or minimizestasis and thrombus creation and enhancing dwell time for an extendedperiod of time.

In a further aspect, a method is provided for creating a bi-directionalmitral isthmus block in a heart. The method includes inserting anocclusion catheter into a CS of the heart, inserting an ablationcatheter into a left atrium of the heart, expanding a balloon on theocclusion catheter, and ablating a portion of the myocardium to create abi-directional isthmus block while the balloon is expanded.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a CS occlusion system in accordance withone embodiment of the invention.

FIG. 2 is a schematic view of an alternative balloon to be used with thecatheter shown in FIG. 1.

FIG. 3 is a schematic view of a further alternative balloon to be usedwith the catheter shown in FIG. 1.

FIG. 4 is a schematic view of a further alternative balloon to be usedwith the catheter shown in FIG. 1.

FIG. 5 is a schematic view of a further alternative balloon to be usedwith an alternative catheter.

FIG. 6 is a schematic diagram of a localization system utilized in anelectrophysiology study.

FIG. 7 illustrates another embodiment of a catheter to anchor anelectrode in a vessel, such as the CS, including a balloon to providebias against the vessel wall.

FIGS. 8-10 depict several actuation mechanisms to actuate a flexibleanchor section of a catheter according to some aspects of the presentinvention.

FIG. 11 depicts the catheter of FIG. 7 deployed within a vessel andillustrates perfusion across the balloon.

FIGS. 12-14 illustrate a balloon catheter that may be anchored within avessel, such as the coronary sinus, to substantially completely occludethe vessel.

DETAILED DESCRIPTION OF THE INVENTION

The invention set forth below in detail describes, depicts, and claimsmethods and systems to create ablation lines in the myocardium andoptionally to generate anatomical geometry (and activation maps and thelike) of at least a portion of said myocardium and also optionally,surrounding tissue. Prior to initiation of the ablation, an occlusioncatheter is positioned within a vessel, such as the coronary sinus (CS),to completely or substantially prevent blood flow therethrough duringthe ablation procedure (i.e., reduce or temporarily halt perfusion).Endocardial ablation is then initiated while the CS is occluded (e.g.,from the left atrium adjacent the CS). It has been found that ablationlines, or lesions, extending completely through the myocardium (i.e.,transmural lesions) that are created near the CS after it has beenoccluded are formed more easily than if the CS were not occluded. In theexample set forth below, it is shown that such occlusion of the CSduring the creation of a mitral isthmus ablation line(s) readily occurs(oftentimes with less power, or energy delivered to target tissue, thanwould be used without occlusion of the CS and/or the time for creationof the ablation line(s) is shorter).

The systems and methods set forth herein are not limited to the specificembodiments described herein. In addition, components of each system andsteps of each method can be practiced independently and separately fromother components and method steps described herein. Each component andmethod step also can be used in combination with other catheters,balloons, systems, and methods, for example.

FIG. 1 illustrates a CS occlusion system 100 in accordance with oneembodiment of the invention. System 100 includes a catheter 102 having adistal end 104 and a proximal end (not shown). In one embodiment, theproximal end of the catheter shaft comprises a braided catheter shaftconstructed for example with 304 stainless steel braid incorporated intoa nylon 11 polymer. An exemplary dimension for the braid is about 0.002″by about 0.006″ (individual filars). Of course, other suitable types, orgrades, of stainless steel can be utilized when practicing the teachingherein, including a braid having one or more substantially flatcross-sectional dimensions (e.g., a “flat braid”). In one form of theinvention the braid, or flat braided portions, are disposed at leastadjacent the proximal portion of the balloon. That is, the catheter 102may also be a braided catheter wherein the catheter wall includes acylindrical and/or flat braid of metal fibers, for example, stainlesssteel fibers (see FIGS. 11 and 12 for general location of such flatbraid denoted by reference numeral 63). Such a metallic braid may beincluded in the catheter 102 to add stability to the catheter 102 andalso to resist radial forces that might crush the catheter 102. Metallicbraid also provides a framework to translate force imparted by theclinician on the proximal end of the catheter 102 to the distal end 104to urge an occlusion structure, such as a balloon 106, disposed on thecatheter 102 into a desired, or appropriate, location, for example. Theflat wire, or other types of wire, braid can be thought of as aso-called backbone for the catheter. In this regard non-provisional U.S.patent application Ser. No. 11/723,729 filed 21 Mar. 2007 assigned toSt. Jude Medical, Atrial Fibrillation Division, Inc. (now U.S. Pat. No.7,706,891) is hereby incorporated herein in its entirety. Othermaterials can be used to fabricate the backbone portion provided thatthey have appropriate mechanical characteristics. One reason forincluding the braided catheter shaft is that stiffer shaft material isdesirable, if not simply necessary, to help the catheter maintain itsposition within the CS when the balloon is inflated and thus continue toocclude the CS. This characteristic of a catheter is sometimes referredto as having adequate “pushability” in certain contexts. Catheter 102has a tubular body with a passageway extending therethrough. A balloon106 is located near distal end 104. In one embodiment, balloon 106 is apolyurethane balloon located 1.5 cm from distal end 104, or at aconvenient and appropriate distance from the distal end 104. It shouldbe recognized that balloon 106 could be manufactured from othermaterials and could be located closer or further from distal end 104than 1.5 cm. In another embodiment, balloon 106 is manufactured from anelastomeric material such as silicone. As shown in FIG. 1, balloon 106has a substantially cylindrical shape, although other shapes can beutilized to increase the likelihood that occlusion of the CS will resultfor a specific anatomical topography of a given patient or subject (asfurther described and depicted herein, and specifically includingsubstantially cylindrical as well as gradually tapered shapes and thelike).

Catheter 102 also includes a plurality of spaced apart marker bands 108located under balloon 106. In one embodiment, catheter 102 includes one,two, or more electrodes or marker bands 108 manufactured from aradio-opaque material, as known in the art, to allow for physiologicsensing, therapy delivery, and/or fluoroscopic visualization of catheter102. In another embodiment, marker bands 108 are located on catheter 102at locations other than under balloon 106. The marker bands can includetraditional radio-opaque material as noted above, such as platinum,gold, steel, or the like and can also, in lieu of or in addition to,these materials include miniature magnetic coils for locating orvisualizing the catheter in vivo (e.g., displaying location,orientation, motion, etc.) using for example one of a variety ofelectroanatomical systems. For example, the EnSite™ impedance-basedsystem or the MediGuide technology magnetic-based system which are bothowned by St. Jude Medical, Inc. of St. Paul, Minn. can be used inconjunction with the occlusion catheter of the invention along withvarious ablation catheters for treating AF. With regard to the MediGuidetechnology, U.S. Pat. No. 6,233,476 to Strommer et al. issued 15 May2001 describes a magnetic-based Medical Positioning System that can beutilized according to this disclosure and the contents of which arehereby incorporated by reference as if fully set forth herein. Also, theAurora system from Northern Digital of Waterloo, Ontario, Canada or theCarto System from Biosense Webster of Diamond Bar, Calif. The systemsinteract with one or more active electrodes coupled to a portion of oneor more catheters (shaft portion, proximal or distal of the balloon,etc.) and used in reference to reference electrodes so that thelocation, orientation, or motion of the catheter can be derived. In thecase of the EnSite™ impedance-based localization and visualizationsystem from St. Jude Medical, Inc. one or more impedance-based referenceelectrodes disposed in a stable position provide spatial reference forother, roving catheters having one or more electrodes. In relatedembodiments, the marker bands 108 and one or more of the electrode pairs112,114 can likewise be adapted for visualization or localizationaccording to the various modalities of the foregoing systems. Of course,while not specifically depicted herein additional structures can becoupled to the catheter 102 for the purpose of visualization andlocalization of the catheter 102 during a procedure on a subject. Inaddition, the balloon itself can include at least one referenceelectrode or magnetic coil for the electroanatomical system such that anocclusion catheter having the balloon (in combination with an optionalrelatively stiffened distal portion) on the catheter shaft retains theelectrode in place thereby increasing positional accuracy to the system.

In addition, the balloon 106,130,150,160,180 can be fabricated from amixture of biocompatible resin-based material infused or combined with aradio-opaque material or can have segments of radio-opaque materialprinted or applied to an interior or exterior surface thereof.

Catheter 102 can include a bend 110 located between balloon 106 anddistal end 104. Bend 110 facilitates cannulization of the CS by allowingeasier access to the CS opening and can promote fixation within aportion of the great cardiac vein distal to the os of the CS. In oneembodiment, bend 110 comprises a single bend of between 25 and 75degrees, and more particularly between 30 and 60 degrees, and moreparticularly still, is about 45 degrees. Bend can also comprise acompound bend or serpentine configuration. In one embodiment, bend 110is located within about four (4) centimeters of distal end 104, and moreparticularly is located within about two (2) centimeters of distal end104, and more particularly still, is located about one and one-half(1.5) centimeters from distal end 104. In addition, catheter 102 can becurved proximally of bend 110. This curvature further facilitatescannulization of the CS as well as proper placement of balloon 106within the CS. In certain forms of the foregoing the distal end 104 isfabricated to include a so-called atraumatic tip portion. In oneembodiment the tip portion is constructed from a relatively lowerdurometer material in relation at least the adjacent portions of themain shaft, or body, of the catheter 102. For example the tip portioncan be fabricated from 35 D polyether block amide (or PEBA) that is, athermoplastic elastomer (TPE), commonly referred to under the trademarkPebax in its unmanufactured form. In this example, the shaft of thecatheter 102 might have a durometer of 45 D-55 D or higher, for example.

Catheter 102 also can include a pair of electrodes 112,114. A firstelectrode pair 112 is located on catheter 102 proximally of balloon 106and a second electrode pair 114 is located on catheter 102 distally ofballoon 106. Electrode pairs 112,114 are utilized to detect the presenceand absence of errant electrical signals in the myocardium (wall of theheart). Each electrode 112,114 is connected to an elongate conductor orlead (not shown) that extends within a lumen or a wall portion of thecatheter 102. In one embodiment, each electrode of the pair ofelectrodes 112,114 comprises a ring-type electrode. By electricallycoupling two of the four depicted electrodes 112,114 to an electrodeseparated from each other by the balloon or expandable member 106 thedesired bi-directional conduction block resulting from an effectivelesion set can be confirmed in substantially real-time during anablation procedure. Alternatively or in addition, one of the distal pairof electrodes 114 can be electrically coupled to a remote electrode (notshown) such as a surface electrode adhered to the skin of a subject orwithin the vicinity of the catheter 102 to confirm conduction block fromwithin the target vessel.

FIG. 2 illustrates an alternative balloon 130 suitable for use withcatheter 102. Balloon 130 is similar to balloon 106 except that balloon130 includes a temperature sensing array 132 having multiple sensors 134positioned such that accurate temperature readings can be obtained ofadjacent tissue. Sensors 134 are positioned at a first end 136 and/or asecond end 138 of balloon 130, at a middle 140 of balloon 130, or at anylocation along balloon 130. In one embodiment, sensors 134 are miniatureT-type thermocouples, thermistors, or any other type of sensor that canbe utilized to sense temperature of adjacent tissue. In exemplaryembodiments, sensors 134 are disposed against an interior surface 142 ofballoon 130, an exterior surface 144 of balloon 130 and/or withinballoon 130 and spaced apart from interior surface 142 of balloon 130.

As shown in FIG. 1, catheter 102 is curved and, accordingly, includes aninner curvature. Array 132 is located at the inner curvature tofacilitate positioning of thermocouple array 132 in the area of themitral isthmus ablation line. In one embodiment, a marker is positionedproximate array 132 to facilitate accurate orientation of balloon 130with regard to the atrial portion of the CS. As shown in FIG. 2, foursensors 134 are arranged in an array that is about two (2) mm wide byabout six (6) mm long, with two (2) mm spacing between sensors. Leads(not shown) extend from each sensor 134 along catheter 102 to a multiplechannel data logger (not shown) connected to a standard computer (notshown) via an RS 232 serial link (not shown).

FIG. 3 illustrates a further alternative balloon 150 suitable for usewith catheter 102. Balloon 150 has a rounded frusto-conical shape thattapers from a proximal end 152 to a distal end 154. In one embodiment,the taper is about a seven (7) degree included angle.

Catheter 102 includes an inflation port (not shown) that is used tosupply fluid to balloons 106,130,150 (etc.). In one embodiment, theinflation fluid is a gas such as air or CO₂. In another embodiment, theinflation fluid is a liquid such as saline or water. In yet anotherembodiment, the fluid can comprise a radio-opaque fluid or so-calledcontrast media to promote visualization of the location and shape of theballoon via fluoroscopy. Along the same lines a relatively inert fluidcould also include minute metallic particles or fibers to promotevisualization or localization. In addition or in lieu of the foregoing aportion of interior or exterior of the balloon can be coated with ametallic film or the like (including magnetic film) to further enhancevisualization or localization of the balloon 106,130,150 (etc.) andhence, the catheter 102 during a procedure utilizing one or more of thevisualization and localization systems noted hereinabove. In a relatedembodiment, a biocompatible resin-based film of material for fabricatingthe balloon can be infused with particles (e.g., so-callednanoparticles, nanotubes, and the like) during the manufacturing processthereby rendering the balloon visible via a number of imagingmodalities.

FIG. 4 illustrates an alternative balloon 160 positioned on catheter102. Balloon 160 includes a plurality of passageways 162 extending froma proximal end 164 of balloon 160 to a distal end 166 of balloon 160.Passageways 162 permit blood to flow therethrough while balloon 160 isinflated and contacting an interior surface of the vessel into whichcatheter 102 has been positioned. Passageways 162 are configured suchthat blood flow will be spaced from the vessel wall thus permitting afluid gap to be located between the flowing blood and the vessel wall.The fluid filling balloon 160 is, in one embodiment, a gas such as oneof air and CO₂. Alternatively, the fluid is a liquid such as water,saline, or Heparinized saline or the like.

FIG. 5 illustrates a further alternative balloon 180 positioned oncatheter 182. A passageway 184 extends through a distal portion 186 ofcatheter 182. Passageway 184 includes a first opening 188 at a positionproximal of a proximal end 190 of balloon 180 and a second opening 192at a position distal of a distal end 194 of balloon 180. In operation,blood is permitted to flow through passageway 184 when balloon 180 isexpanded and contacting an interior surface of the vessel into whichcatheter 182 has been positioned.

The method of using the above described CS occlusion system (shown inFIGS. 1-3) will next be described.

A sheath containing the occlusion catheter is inserted into one of thefemoral artery and the internal jugular. In one embodiment, the sheathis an 8 Fr, Fast Cath™ model, available from St. Jude Medical, Inc. ofSt. Paul, Minn. The sheath is manipulated through the vascular system sothat it enters a chamber of the heart, such as the left atrium. Theocclusion catheter is extended distally from the sheath until theballoon on the catheter is distal of the distal end of the introducersheath. The catheter is manipulated to allow a distal tip of thecatheter to enter the vessel to be occluded. The extended catheter isinserted into the vessel such that the balloon is at least partiallywithin the vessel. In one embodiment, the vessel is the CS and theballoon is completely contained within the vessel and located adjacentto, and/or overlying, a portion of the myocardium to be ablated. In theembodiment illustrated in FIGS. 1-3, a pair of marker bands is includedon the catheter. These marker bands promote accurate placement of thecatheter within the vessel to be occluded and can be used to aidelectroanatomical visualization and localization as described elsewhereherein.

An ablation catheter is then manipulated through the vascular system sothat the ablation catheter enters a chamber of the heart, such as theleft atrium. In one embodiment, the ablation catheter also includesdiagnostic capability used to map relevant geometries and/or electricalactivity within the chamber. When the ablation catheter is locatedwithin the left atrium, such geometries include one or more of the leftatrial appendage, the right superior pulmonary vein, the inferiorpulmonary trunk, and the left atrial body. In an alternative embodiment,the above described mapping is performed using a separate mapping systemcoupled to a mapping and/or therapy delivery catheter. As noted hereinan exemplary mapping system includes the EnSite system with NavX surfacepatches (or the EnSite Velocity version of the EnSite system), availablefrom St. Jude Medical, Inc.

The ablation catheter is then utilized to ablate portions of themyocardium. The ablation energy and delivery technology includes, by wayof example and without limitation one or more of the following:cryogenic, RF, laser, microwave, ultrasound (including high intensityfocused ultrasound, or HIFU) and microwave. In one embodiment, ablationlesions are created on the atrial myocardium overlying the CS. Theablation lesions extend through the myocardium and prevent errantelectrical signals from passing across the portion of the myocardiumthat has been ablated. In an exemplary embodiment, an ablation lesion iscreated that extends from proximate the left inferior pulmonary vein toproximate the mitral valve. Such an ablation lesion is sometimesreferred to as a mitral isthmus line. It is this region of themyocardium that overlies the CS. Accordingly, when the CS is occluded,blood does not flow adjacent this portion of the myocardium and it hasbeen found that a lower power setting can be used on the ablationcatheter and/or the ablation is completed within a shorter time, thanwhen blood is flowing through the CS.

According to an aspect of the invention a gas filled balloon is locatedwithin the portion of the CS that is adjacent to, and/or overlies thisportion of the myocardium, and thus heat is not removed from themyocardium as efficiently as when blood is flowing through the CS. Theabsence of significant reduction of blood flow thus allows moreefficient and relatively rapid ablation of this portion of themyocardium. In one embodiment, due at least in part to this increasedefficiency, ablating within the CS is not used when the above describedCS occlusion catheter is used. In another embodiment, due at least inpart to the increased efficiency, the number of ablation lesions createdwhen the above described CS occlusion catheter is used is less than whenthe CS occlusion catheter is not used.

As described above, located on the occlusion catheter is a pair ofelectrodes. These electrodes are utilized to determine whether errantelectrical signals are passing through the portion of the myocardiumbeing monitored. In one embodiment, the occlusion catheter is used tomonitor these signals before, during, and/or after the ablationprocedure, and to gather information so that a determination can be madeas to whether the ablation procedure has stopped the errant electricalsignals.

FIG. 1 shows a schematic diagram of a localization system 8 forconducting cardiac electrophysiology studies by navigating a cardiaccatheter and measuring electrical activity occurring in a heart 10 of apatient 11 and three-dimensionally mapping the electrical activityand/or information related to or representative of the electricalactivity so measured. System 8 can be used, for example, to create ananatomical model of the patient's heart 10 using one or more electrodes.System 8 can also be used to measure electrophysiology data at aplurality of points along a cardiac surface, and store the measured datain association with location information for each measurement point atwhich the electrophysiology data was measured, for example to create adiagnostic data map of the patient's heart 10. As one of ordinary skillin the art will recognize, and as will be further described below,localization system 8 determines the location of objects, typicallywithin a three-dimensional space, and expresses those locations asposition information determined relative to at least one reference.

For simplicity of illustration, the patient 11 is depicted schematicallyas an oval. Three sets of surface electrodes (e.g., patch electrodes)are shown applied to a surface of the patient 11, defining threegenerally orthogonal axes, referred to herein as an x-axis, a y-axis,and a z-axis. The x-axis surface electrodes 12, 14 are applied to thepatient along a first axis, such as on the lateral sides of the thoraxregion of the patient (e.g., applied to the patient's skin underneatheach arm) and may be referred to as the Left and Right electrodes. They-axis electrodes 18,19 are applied to the patient along a second axisgenerally orthogonal to the x- axis, such as along the inner thigh andneck regions of the patient, and may be referred to as the Left Leg andNeck electrodes. The z-axis electrodes 16,22 are applied along a thirdaxis generally orthogonal to both the x-axis and the y-axis, such asalong the sternum and spine of the patient in the thorax region, and maybe referred to as the Chest and Back electrodes. The heart 10 liesbetween these pairs of surface electrodes 12/14, 18/19, and 16/22.

An additional surface reference electrode (e.g., a “belly patch”) 21provides a reference and/or ground electrode for the system 8. The bellypatch electrode 21 may be an alternative to a fixed intra cardiacelectrode 31, described in further detail below. It should also beappreciated that, in addition, the patient 11 may have most or all ofthe conventional electrocardiogram (ECG) system leads in place. This ECGinformation is available to the system 8, although not illustrated inFIG. 6.

A representative catheter 13 having at least one electrode 17 (e.g., adistal electrode) is also shown. This representative catheter electrode17 is referred to as the “roving electrode,” “moving electrode,” or“measurement electrode” throughout the specification. Typically,multiple electrodes on catheter 13, or on multiple such catheters, willbe used. In one embodiment, for example, localization system 8 maycomprise up to sixty-four electrodes on up to twelve catheters disposedwithin the heart and/or vasculature of the patient. Of course, thisembodiment is merely exemplary, and any number of electrodes andcatheters may be used within the scope of the present invention.

An optional fixed reference electrode 31 (e.g., attached to a wall ofthe heart 10) is shown on a second catheter 29. For calibrationpurposes, this electrode 31 may be stationary (e.g., attached to or nearthe wall of the heart and/or in the CS) or disposed in a fixed spatialrelationship with the roving electrodes (e.g., electrodes 17,52,54,56),and thus may be referred to as a “navigational reference” or “localreference.” The fixed reference electrode 31 may be used in addition oralternatively to the surface reference electrode 21 described above. Inmany instances, a coronary sinus electrode or other fixed electrode inthe heart 10 can be used as a reference for measuring voltages anddisplacements; that is, as described below, fixed reference electrode 31may define the origin of a coordinate system.

Each surface electrode is coupled to the multiplex switch 24, and thepairs of surface electrodes are selected by software running on acomputer 20, which couples the surface electrodes to a signal generator25. The computer 20, for example, may comprise a conventionalgeneral-purpose computer, a special-purpose computer, a distributedcomputer, or any other type of computer. The computer 20 may compriseone or more processors, such as a single central processing unit (CPU),or a plurality of processing units, commonly referred to as a parallelprocessing environment, which may execute instructions to practice thevarious aspects of the present invention described herein.

Generally, three nominally orthogonal electric fields are generated by aseries of driven and sensed electric dipoles (e.g., surface electrodepairs 12/14, 18/19, and 16/22) in order to realize catheter navigationin a biological conductor. Alternatively, these orthogonal fields can bedecomposed and any pairs of surface electrodes can be driven as dipolesto provide effective electrode triangulation. Additionally, suchnon-orthogonal methodologies add to the flexibility of the system. Forany desired axis, the potentials measured across the roving electrodesresulting from a predetermined set of drive (source-sink) configurationsmay be combined algebraically to yield the same effective potential aswould be obtained by simply driving a uniform current along theorthogonal axes.

Thus, any two of the surface electrodes 12,14,16,18,19,22 may beselected as a dipole source and drain with respect to a groundreference, such as belly patch 21, while the unexcited electrodesmeasure voltage with respect to the ground reference. The rovingelectrodes 17,52,54,56 placed in the heart 10 are exposed to the fieldfrom a current pulse and are measured with respect to ground, such asbelly patch 21. In practice the catheters within the heart may containmore or fewer electrodes than the four shown, and each electrodepotential may be measured. As previously noted, at least one electrodemay be fixed to the interior surface of the heart to form a fixedreference electrode 31, which is also measured with respect to ground,such as belly patch 21, and which may be defined as the origin of thecoordinate system relative to which localization system 8 measurespositions. Data sets from each of the surface electrodes, the internalelectrodes, and the virtual electrodes may all be used to determine thelocation of the roving electrodes 17,52,54,56 within heart 10.

The measured voltages may be used to determine the location inthree-dimensional space of the electrodes inside the heart, such asroving electrodes 17,52,54,56, relative to a reference location, such asreference electrode 31. That is, the voltages measured at referenceelectrode 31 may be used to define the origin of a coordinate system,while the voltages measured at roving electrodes 17,52,54,56 may be usedto express the location of roving electrodes 17,52,54,56 relative to theorigin. Preferably, the coordinate system is a three-dimensional (x, y,z) Cartesian coordinate system, though the use of other coordinatesystems, such as polar, spherical, and cylindrical coordinate systems,is within the scope of the invention.

As should be clear from the foregoing discussion, the data used todetermine the location of the electrode(s) within the heart is measuredwhile the surface electrode pairs impress an electric field on theheart. The electrode data may also be used to create a cardiac geometryincluding a respiration compensation value used to improve the rawlocation data for the electrode locations as described in U.S. Pat. No.7,263,397 to Hauck et al. issued 28 Aug. 2007 hereby incorporated hereinin its entirety. The electrode data may also be used to compensate forchanges in the impedance of the body of the patient as described inco-pending U.S. patent application Ser. No. 11/227,580, filed on 15 Sep.2005, which is also incorporated herein by reference in its entirety.

In summary, the system 8 first selects a set of surface electrodes andthen drives them with current pulses. While the current pulses are beingdelivered, electrical activity, such as the voltages measured at leastone of the remaining surface electrodes and in vivo electrodes, ismeasured and stored. Compensation for artifacts, such as respirationand/or impedance shifting, may be performed as indicated above.

In a preferred embodiment, the localization/mapping system is the EnSiteNavX™ navigation and visualization system of St. Jude Medical, AtrialFibrillation Division, Inc., which generates the electrical fieldsdescribed above. Other localization systems, however, may be used inconnection with the present invention, including for example, the Cartonavigation and location system of Biosense Webster, Inc., the MediGuidetechnology owned by St. Jude Medical, Inc., or the Aurora system ofNorthern Digital Inc., both of which utilize magnetic fields rather thanelectrical fields. The localization and mapping systems described in thefollowing patents (all of which are hereby incorporated by reference intheir entireties) can also be used with the present invention: U.S. Pat.Nos. 6,990,370; 6,978,168; 6,947,785; 6,939,309; 6,728,562; 6,640,119;5,983,126; and 5,697,377.

The fields generated by localization system 8, whether an electricalfield (e.g., EnSite NavX™), a magnetic field (e.g., Carto, MediGuidetechnology, Aurora), or another suitable field, may be referred togenerically as “localization fields,” while the elements generating thefields, such as surface electrodes 12,14,16,18,19,22 may be genericallyreferred to as “localization field generators.” As described above,surface electrodes 12,14,16,18,19,22 may also function as detectors tomeasure the characteristics of the localization field (e.g., thevoltages measured at roving electrodes 17,52,54,56). Though the presentinvention will be described primarily in the context of a localizationsystem that generates an electrical field, one of ordinary skill in theart will understand how to apply the principles disclosed herein inother types of localization fields (e.g., by replacing electrodes17,52,54,56 with coils to detect different components of a magneticfield).

As described above, localization system 8 may employ one or morereference electrodes 31, carried on one or more catheters 29, as areference for the three-dimensional coordinate system of localizationsystem 8. Accordingly, it is desirable for reference electrodes 31 to bepositively retained (often referred to as “anchored”) at the desiredlocation for the reference of the three-dimensional coordinate system,often within the CS.

FIG. 7 illustrates another embodiment of a catheter to anchor anelectrode in a vessel, such as the CS, including a balloon to providebias against the vessel wall. FIG. 7 illustrates a second embodiment ofa catheter 60 having an anchor section 66 for anchoring one or moreelectrodes 62 within a CS. In the embodiment illustrated in FIG. 7,anchor section 66 includes at least one balloon 72 positioned about acircumference of catheter body 64. Balloon 72 is fluidly coupled to aninflation fluid source (not shown), in order to inflate balloon 72 fromthe undeployed configuration (not illustrated) into the deployedconfiguration (illustrated in FIG. 7), for example through inflationport 73 (shown in FIG. 11). Perfusion pathways may be provided by one ormore perfusion passages through the interior of catheter 60, each ofwhich includes a first opening 74 positioned distally of anchor section66 (e.g., distally of balloon 72) and a second opening 76 positionedproximally of anchor section 66 (e.g., proximally of balloon 72).Alternatively, perfusion pathways may be provided by altering the shapeof balloon 72 such that it does not completely occlude the CS, therebypermitting perfusion around the exterior of catheter 60.

FIGS. 8-10 depict several actuation mechanisms to actuate a flexiblesection 80 of a catheter body 111 according to some aspects of thepresent invention. FIGS. 8-10 illustrate various actuating mechanisms(denoted generally by an arrow from reference numeral 80) for a flexibleanchor segment positioned at the distal end 64 of catheter body 111. InFIG. 8, the actuating mechanism or assembly 82 includes a joint having apin 84 joining two members 86,88 such that when a tension member 90(e.g., two elongate wires or filaments as shown in FIG. 8) the distalend 64 deflects. In FIG. 9 the actuating mechanism or assembly includesa pleated or corrugated section (also denoted by reference numeral 82)which is also activated by wires or filaments 90 to deflect the distalend 64 relative to the catheter body 111. In FIG. 10, the actuatingmechanism or assembly includes a hinge assembly (denoted by referencenumeral 82) activated by wires or filaments 90 so that the distal end 64pivots relative to catheter body 111.

The devices and methods disclosed herein may be practiced to goodadvantage in generating a cardiac geometry. A CS catheter having ananchor structure and an electrode may be provided and introduced intothe CS. Once the catheter is positioned as desired, the anchor structuremay be deployed to engage a tissue surface of the CS, thereby inhibitingrelative movement between the CS catheter (and therefore any electrodesthereon) and the CS. The anchor structure may be any of the structuresdisclosed herein (e.g., sections of the catheter body having anexpandable axial cross-section, wire anchors, anchor segments of thecatheter body, and the like). With the electrodes so anchored, they maybe used as reference electrodes for a cardiac mapping operation. Asnoted, the catheter may also be configured to preserve perfusion via apathway through the CS from a distal side of the anchor structure orballoon to the other. As described above, the at least one perfusionpathway may be around the exterior of the catheter body and/or throughthe interior of the catheter body to thereby bypass the balloon andprovide a modicum of perfusion.

Occasionally, it may be desirable to provide a catheter 131 thatcompletely occludes the CS. This may be desirable, for example, wherecatheter 131 is to be employed in conjunction with an ablationprocedure. In such contexts, blood flow through the CS may act as a heatsink, pulling heat away from an ablation site and preventing lesioncreation. By occluding the CS, this heat sink effect may be mitigated.

FIG. 11 depicts the catheter of FIG. 7 deployed within a vessel andillustrates limited, or highly reduced, perfusion “across” the balloon.This prevents catheter 60 from completely occluding the CS, even withanchor segment 66 in the deployed configuration, thereby minimizingstasis and thrombus creation and advantageously increasing dwell time ofcatheter 60 within the CS during a cardiac mapping operation.

FIG. 7 illustrates a second embodiment of a catheter 60 having an anchorsection 66 for anchoring one or more electrodes 62 within a CS. In theembodiment illustrated in FIG. 7, anchor section 66 includes at leastone balloon 72 positioned about a circumference of catheter body 64.Balloon 72 is fluidly coupled to an inflation fluid source (not shown),in order to inflate balloon 72 from the undeployed configuration (notillustrated) into the deployed configuration, for example throughinflation port 73 (shown in FIG. 11). Perfusion pathways may be providedby one or more perfusion passages through the interior of catheter 60,each of which includes a first opening 74 positioned distally of anchorsection 66 (e.g., distally of balloon 72) and a second opening 76positioned proximally of anchor section 66 (e.g., proximally of balloon72). Alternatively, perfusion pathways may be provided by altering theshape of balloon 72 such that it does not completely occlude the CS,thereby permitting perfusion around the exterior of catheter 60. Alsodepicted in FIG. 11 (and FIG. 12) is a region proximal of the balloon 72that includes structural reinforcement (denoted generally by referencenumeral 63) to enhance the so-called pushability of the distal end and,in particular the balloon 72 during CS occlusion. The structuralreinforcement 63 can include an embedded braided segment of the shaft ofthe catheter including one or more flat wire filars (e.g., wire having alateral dimension greater than an axial dimension). The structuralreinforcement 63 can extend partially or wholly toward the proximal endof the catheter but in the case that the catheter is deployed within adelivery sheath or introducer, the structural reinforcement 63 does notnecessarily need to extend all the way to the proximal end of thecatheter.

FIGS. 12-14 illustrate a balloon catheter that may be anchored within avessel, such as the CS, to substantially completely occlude the vessel.Accordingly, as shown in FIGS. 12-14, catheter 131 may include anelongate catheter body 135 and a balloon 133, as well as one or moreelectrodes (e.g., electrodes 62). When balloon 133 is deflated (FIG.14), catheter 131 may be introduced into and/or removed from the CS.When balloon 133 is inflated (FIG. 12), it occludes the CS. Of course,balloon 133 also serves to anchor catheter 131 relative to the CS.

Although several embodiments of this invention have been described abovewith a certain degree of particularity, those skilled in the art couldmake numerous alterations to the disclosed embodiments without departingfrom the spirit or scope of this invention. For example, though thereference electrode has been described herein as anchored in the CS, theprinciples disclosed herein could be employed to anchor the referenceelectrode in any blood vessel.

Similarly, though the electrode has been described herein as a referenceelectrode for a localization system, the devices and methods describedcould also be practiced to position a therapeutic element, such as an RFablation electrode or other ablation element.

In a further embodiment, the occlusion system includes an introducersheath utilized to position the occlusion catheter at the CS. In thisembodiment, the catheter extends through the introducer sheath and, uponarrival at the CS, is extended distally beyond a distal end of theintroducer sheath. In one embodiment, the sheath is a steerable sheaththat can be manipulated through the use of wires or other means to bendor curve as it passes through the vascular system, thus bending orcurving the catheter therewithin. As noted with respect to the catheter,either or both of the catheter and the sheath can include reinforcedportion(s) at least near the balloon to enhance the pushability of eachto provide stability to the balloon during CS occlusion. Such reinforcedportions can include, for example, braided portions having one or morefilars of flat wire braid, or the like.

EXAMPLE A

Experiments were conducted on nine female pigs using the aboveidentified occlusion system. Vascular access was obtained via standardangiography sheaths in the right femoral artery (8Fr, Fast Cath™ model,available from St. Jude Medical, Inc. of Little Canada, Minn.) and theright internal jugular (10Fr).

Transseptal access was obtained under fluoroscopic guidance with a DaigSL-1 sheath (available from St. Jude Medical, Inc.). A quadripolarelectrode, placed in the right coronary cusp, was used as a referencefor the electroanatomical mapping system (EnSite NavX, St. Jude Medical,Inc.). Separate geometries and associated electrical activity of theleft atrial appendage, the right superior pulmonary vein, the inferiorpulmonary trunk, and the left atrial body were acquired using a circularmapping catheter.

Ablation was performed using a 3.5 mm Celsius Thermo-Cool (availablefrom Biosense Webster, Inc. of Diamond Bar, Calif). A maximum of 35watts power was used in the last seven (7) swine and 50 watts were usedin the first 2 animals. All RF ablations were performed for one (1)minute with an irrigation rate of about 30 cc/min.

For each swine, two linear ablations lines (proximal and distal) werecreated over the atrial myocardium overlying the CS. The proximal linewas placed more between the inferior border of the inferior pulmonaryvein trunk and the mitral annulus. The distal line was located betweenthe inferior border of the left atrial appendage and the mitral annulus.In each swine, the CS was completely occluded with the CS occlusionballoon during RF ablation for one of the lines. The CS occlusionballoon was positioned with the center of the balloon under the ablationline. The CS balloon was then inflated with approximately five (5) mlsof air and occlusion of the CS and the great cardiac vein was confirmedby contrast injection through the catheter internal lumen. The positionof the line that was created during CS occlusion was alternated betweenswine. The CS balloon was removed during RF application for the ablationline without occlusion to prevent blood flow limitation. Biophysicalparameters of each RF application were continuously recorded in theelectrophysiology recording system.

The CS occlusion catheter utilized is illustrated in FIG. 2.

At the end of the procedure, 2,3,5-triphenyl-2H-tetrazolium chloride wasadministered intravenously and the animals were euthanized with anintravenous injection of Euthasol 20m1 (390 mg pentobarbital sodium and50 mg phenytoin sodium per ml, Delmarva Laboratory, Midlothian, Va.). Alateral thoracotomy was then performed with an incision through the left4th intercostal space. The heart was examined in situ for the presenceof pericardial bleeding. The endocardial surface of the excised heartwas then examined by creating an incision in the left atrium to allowinspection and photography of the left atrial aspect of the mitralisthmus.

The CS was opened posteriorly through its free wall for inspection ofpossible dissection and to assess transmurality of each line. Ablationlines were also examined and photographed longitudinally with a macrocamera (Nikon D50, Micro Nikkor 60 mm f2.8, Nikon Corporation, Melville,N.Y., USA) to assess transmurality and for off-line measurements.Ablation lesion characteristics were measured using custom softwarewritten with the Matlab programming language (Mathworks).

A total of 18 endocardial ablation lines were placed over the CS for thenine swine used in the study (i.e. a proximal and distal line for eachswine). In one swine, the occlusion balloon could not be properlypositioned and therefore two lines were placed without CS occlusion.Therefore, eight (8) ablation lines were placed during CS balloonocclusion and 10 lines were placed without CS occlusion. All lines wereidentified at necropsy. However, at post mortem examination, one of theproximal ablation lines was found to be located within the left atrialappendage superior to the CS and therefore, this line was not includedin the data analysis.

The left atrial wall thickness was 2.9±1.3 mm for the endocardial lineswithout CS occlusion and 3.4±1.1 mm for the endocardial lines with CSocclusion (p=0.5). Similarly, the mean number of RF applications was6.2±1.5 and 6.3±1.2 respectively during CS occlusion and when the CSballoon was not inflated. Catheter temperature and mean power were notsignificantly different when CS occlusion was compared to no-occlusion.Moreover, impedance drop was not different between these two conditions.

All linear lesions deployed during CS occlusion were transmural.Conversely, only one (1) out of 10 lines was transmural when the CS wasopen. Overall, RF applications were sufficient to create lesion depth upto 76%±18% of the left atrial wall.

No device related adverse events were seen during the procedures. Anepicardial hemorrhagic pericarditis was seen in the first animal(compatible with previous myocarditis, and unlikely to be related to thedevice). These finding were not seen in the subsequent eight (8)animals. The lungs were normal and the CS was normal upon post mortemexamination in all animals. No blood clots were observed. The balloonwas intact in all devices tested.

EXAMPLE SET B

The following numbered sentences are intended as illustrative and notlimiting as to the subject matter contemplated per this disclosure andto provide some context to those of skill in the art as to theprocedures contemplated herein.

1. A method for ablating a portion of myocardium located adjacent to acoronary vessel of a heart, said method comprising:

inserting an occlusion catheter having an expandable film of materialaround a distal portion thereof into a coronary vessel of a heart,wherein said occlusion catheter includes a reinforcing layer of materialwithin at least a portion of a shaft of the catheter near a proximal endof the expandable film of material;

one of at least partially and fully occluding blood flow within thevessel using the occlusion catheter with the expandable film of materialin an expanded state disposed in contact with one of the ostium of thevessel and an inner surface of the vessel;

inserting an ablation catheter into a chamber of the heart;

positioning the ablation catheter against a portion of myocardiumadjacent the vessel; and

ablating the portion of the myocardium adjacent the vessel while thevessel is at least partially occluded.

2. A method in accordance with example 1, wherein inserting an occlusioncatheter comprises inserting a distal end portion of the occlusioncatheter distal to the expandable film of material into a portion of avein branching from a CS, and wherein the distal end portion is eithercomprised of a material having a softer elasticity modulus relative toproximal portions of the occlusion catheter or is free of thereinforcing layer of material.

3. A method in accordance with example 2, wherein occluding the vesselcomprises inflating a balloon on the occlusion catheter to occlude thevessel, after the occlusion catheter has been inserted into the portionof the vein.

4. A method in accordance with example 1, wherein inserting an ablationcatheter comprises inserting the ablation catheter through a portion ofinteratrial septal wall and into a left atrium of the heart.

5. A method in accordance with example 1, wherein positioning theablation catheter comprises positioning a distal portion of the ablationcatheter proximate the vessel.

6. A method in accordance with example 1, wherein ablating a portion ofthe myocardium comprises creating a mitral isthmus ablation line.

7. A method in accordance with example 1, wherein ablating a portion ofthe myocardium comprises creating a transmural lesion in a regionbetween the mitral annulus and the left inferior pulmonary vein ostium.

8. A method in accordance with example 1, further comprising atemperature sensor coupled to the occlusion catheter for sensingtemperatures of adjacent tissues.

9. A method in accordance with example 1, further comprising utilizingthe occlusion catheter to determine whether errant electrical signalsare present in the myocardium.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural or methodelements that do not differ from the literal language of the claims, orif they include equivalent structural or method elements withinsubstantial differences from the literal languages of the claims.

All directional references (e.g., upper, lower, upward, downward, left,right, leftward, rightward, top, bottom, above, below, vertical,horizontal, clockwise, and counterclockwise) are only used foridentification purposes to aid the reader's understanding of the presentinvention, and do not create limitations, particularly as to theposition, orientation, or use of the invention. Joinder references(e.g., attached, coupled, connected, and the like) are to be construedbroadly and may include intermediate members between a connection ofelements and relative movement between elements, As such, joinderreferences do not necessarily infer that two elements are directlyconnected and in fixed relation to each other.

It is intended that all matter contained in the above description orshown in the accompanying drawings shall be interpreted as illustrativeonly and not limiting. Changes in detail or structure may be madewithout departing from the spirit of the invention as defined in theappended claims.

1-21. (canceled)
 22. A method for ablating a portion of an atrium of aheart using non-cryogenic energy in the portion, said method comprising:inserting an occlusion catheter into a vessel on or in the heart;occluding a section of the vessel using the occlusion catheter, whereinthe occluded vessel section and the portion of the atrium share and areseparated by an intervening myocardial wall; inserting an ablationcatheter into the atrium; positioning the ablation catheter against aninner surface of the intervening myocardial wall; and transmittingnon-cryogenic energy in the portion of the atrium to ablate the portionof the atrium while the vessel section is occluded.
 23. The method ofclaim 22 wherein inserting the occlusion catheter comprises insertingthe occlusion catheter into a coronary sinus.
 24. The method of claim 22wherein occluding the portion of the vessel comprises inflating aballoon on the occlusion catheter to occlude the portion of the vessel.25. The method of claim 22 wherein ablating the portion of the atriumcomprises one of: creating a mitral isthmus ablation line, creating anendocardial ablation, and creating a transmural lesion in a regionbetween the mitral annulus and the left inferior pulmonary vein ostium.26. The method of claim 22 further comprising utilizing the occlusioncatheter to sense temperatures of adjacent tissues.
 27. The method ofclaim 22 further comprising utilizing an electrode coupled with theocclusion catheter to determine whether errant electrical signals arepresent in the atrium.
 28. The method of claim 22, wherein a source ofthe non-cryogenic energy comprises radio frequency (RF), laser,microwave, ultrasound (including high intensity focused ultrasound, orHIFU).
 29. A method for ablating a portion of an atrial myocardium usingnon-cryogenic energy, said method comprising: inserting a ballooncatheter into a vessel on or of the heart; inserting an ablationcatheter into a left atrium of a heart; and transmitting non-cryogenicenergy in the portion of the atrial myocardium to ablate the portion ofthe atrium while a balloon on the balloon catheter is expanded; whereinthe balloon catheter is expanded in a portion of the vessel that sharesan intervening wall with, and is separated by the intervening wall from,the portion of the atrial myocardium.
 30. The method of claim 29 furthercomprising supplying a fluid to the balloon on the balloon catheter andexpanding the balloon to contact an inner wall of the vessel.
 31. Themethod of claim 30 wherein expanding the balloon comprises occluding thevessel.
 32. The method of claim 29 wherein ablating the portion of theatrial myocardium further comprises ablating the myocardium fromproximate the pulmonary vein to proximate the mitral valve.
 33. Themethod of claim 29 further comprising utilizing an electrode coupledwith the balloon catheter to determine whether errant electrical signalsare present in the myocardium.
 34. The method of claim 29 furthercomprising sensing temperatures of tissues adjacent the balloon duringthe ablation.
 35. The method of claim 29, wherein a source of thenon-cryogenic energy comprises radio frequency (RF), laser, microwave,ultrasound (including high intensity focused ultrasound, or HIFU). 36.An occlusion catheter comprising: a catheter body having a distalportion and a pre-formed bend located in the distal portion, thepre-formed bend configured to facilitate cannulization of said distalportion in a vessel; a balloon located proximal of the pre-formed bendand comprising an outer wall configured to contact an inner surface ofthe vessel when inflated and positioned therewithin, wherein the balloondefines: a longitudinal lumen through which said catheter body extends;and at least one passageway extending from a first opening in the outerwall of the balloon to a second opening in the outer wall of theballoon, the at least one passageway having a longitudinal axis centeredin the at least one passageway different from an axis centered in thelongitudinal lumen, the at least one passageway configured to permitblood to flow through the balloon while the balloon is inflated andcontacting the inner surface of the coronary sinus and both the firstopening and the second opening are within the vessel; a plurality ofmarker bands positioned on the catheter body; and a plurality ofelectrodes positioned on the catheter body.
 37. The occlusion catheterof claim 36 wherein the plurality of marker bands are located within theballoon.
 38. The occlusion catheter of claim 36 further comprising atleast one sensor attached to one of: an interior surface of the balloon,an exterior surface of the balloon, and within the balloon and spacedapart from an interior surface of the balloon.
 39. The occlusioncatheter of claim 38 wherein the at least one sensor comprises atemperature sensor configured to detect a temperature of adjacenttissue.
 40. The occlusion catheter of claim 36 wherein the occlusioncatheter has at least one of: an angle of the pre-formed bend is between30 and 60 degrees; and the pre-formed bend is located within about twocentimeters of a distal end of the catheter body.
 41. The occlusioncatheter of claim 36 wherein the balloon has one of a tapered shape anda rounded frusto-conical shape.
 42. The occlusion catheter of claim 35,wherein the at least one passageway is parallel with the longitudinallumen.